Divisibility Game
Number Rule Example
2 If the number ends in 0, 2, 4, 6, or 8 134 → yes (ends in 4)
3 If the sum of the digits is divisible by 3 147 → 1+4+7=12 → yes
4 If the last two digits form a number divisible by 4 212 → 12 →
yes
5 If it ends in 0 or 5 835, 400 → yes
6 If it's divisible by both 2 and 3 114 → ends in 4 & 1+1+4=6 →
yes
7 A bit tricky: double the last digit, subtract from the rest. If the result
is divisible by 7, then so is the number. 203 → 20 - (2×3) =14 → yes
8 If the last 3 digits form a number divisible by 8 1,000 → 000 → yes
9 If the sum of the digits is divisible by 9 729 → 7+2+9=18 → yes
10 Ends in 0 190 → yes
11 Take the digits of the number and “- + - + …” them from left to
right. If the result is divisible by 11 (including 0), then the original
number is divisible by 11.
E.g. 594 5-9+4=0 0 is divisible by 11→594 is divisible by 11
3,432 3−4+3−2=0 0 is divisible by 11 →3,432 is divisible
by 11
Game 1: “Who’s It Divisible By?” Mathex
Game 2: “Divisibility Mystery”
How to Play:
1. Give clues about a number using divisibility rules.
2. Students try to guess the number based on the clues.
Example:
"I am a 3-digit number.
I'm divisible by 3, but not 2.
The sum of my digits is 12.
I end in 5."
Answer: Could be 375
Numbers:
231: divisible by 3, 7
480: divisible by 2, 4, 5, 8, 10
135: divisible by 3, 5, 9
552: divisible by 2, 3, 4, 6, 8
495: divisible by 3, 5, 9, 11
210: divisible by 2, 3, 5, 6, 7
306: divisible by 2, 3, 6, 9
150: divisible by 2, 3, 4, 5, 6, 10
2310: divisible by 2, 3, 5, 6,7,11
